Electronic device assemblies including conductive vias having two or more conductive elements

ABSTRACT

Electronic devices include a substrate with first and second pairs of conductive traces extending in or on the substrate. A first conductive interconnecting member extends through a hole in the substrate and communicates electrically with a first trace of each of the first and second pairs, while a second conductive interconnecting member extends through the hole and communicates electrically with the second trace of each of the first and second pairs. The first and second interconnecting members are separated from one another by a distance substantially equal to a distance separating the conductive traces in each pair. Electronic device assemblies include a transmitting device configured to transmit a differential signal through a conductive structure to a receiving device. The conductive structure includes first and second pair of conductive traces with first and second interconnecting members providing electrical communication therebetween.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.11/359,863, filed Feb. 22, 2006, now U.S. Pat. No. 7,767,913, issuedAug. 3, 2010, which application is related to U.S. patent applicationSer. No. 11/868,899, filed Oct. 8, 2007, now U.S. Pat. No. 7,495,316,issued Feb. 24, 2009, for “Methods of Forming Conductive Vias andMethods of Forming Multichip Modules Including Such Conductive Vias;”U.S. patent application Ser. No. 11/405,045, filed Apr. 17, 2006, nowU.S. Pat. No. 7,355,267, issued Apr. 8, 2008, for “Substrate,Semiconductor Die, Multichip Module, and System Including a ViaStructure Comprising a Plurality of Conductive Elements;” U.S. patentapplication Ser. No. 11/351,006, filed Feb. 8, 2006, now U.S. Pat. No.7,282,784, issued Oct. 16, 2007, for “Methods of Manufacture of a ViaStructure Comprising a Plurality of Conductive Elements and Methods ofForming Multichip Modules Including Such Via Structures;” and U.S.patent application Ser. No. 10/931,959, filed Aug. 31, 2004, now U.S.Pat. No. 7,129,567, issued Oct. 31, 2006, for “Substrate, SemiconductorDie, Multichip Module, and System Including a Via Structure Comprising aPlurality of Conductive Elements.” The disclosure of each of theabove-referenced patents is hereby incorporated herein by this referencein their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to conductive vias for use incircuit boards, semiconductor dice and wafers, interposers, and othersubstrates. More particularly, the present invention relates toconductive vias that have two or more conductive elements that arespaced substantially the same distance apart from one another as are theconductive traces that electrically communicate with the conductiveelements of the via. The present invention also relates to methods forenabling electrical communication between at least two electronicdevices using a circuit board using such conductive vias, and to methodsfor establishing electrical communication between at least twoelectronic devices through a substrate using such conductive vias.

2. Discussion of Related Art

Circuit boards (often referred to as “printed circuit boards,” “wiringboards,” or “printed wiring boards”) are used in electronic devices tomechanically hold and to provide electrical communication between theelectrical components thereof. Electrical components such astransistors, resistors, and capacitors may be soldered into a circuitboard and electrically interconnected by electrically conductive signaltraces formed within or on the surfaces of the circuit board.Semiconductor chips, semiconductor chip packages, and semiconductor chipmodules may be provided that include a number of pins, which may beinserted into corresponding holes in the circuit board and soldered inplace. Such chips, packages, and modules may include, for example,microprocessors, dynamic random access memories (DRAMs), static randomaccess memories (SRAMs), and application specific integrated circuits(ASICs), and may each have hundreds or thousands of electricallyconductive terminals requiring electrical interconnection with theconductive traces of a circuit board. The electrically conductive tracesin the circuit board are used to interconnect the semiconductor chipdevices and the electrical components.

Circuit boards generally are substantially planar and include one ormore dielectric layers that include an electrically insulating material(such as, for example, ceramic-based materials, polymer-based materials,Bismaleimide Triazine (BT), FR-4 laminates, and FR-5 laminates), and twoor more conductive layers. The conductive layers may include a pluralityof conductive traces, and each conductive layer may be carried by ordisposed between surfaces of the dielectric layers.

The layered structure of the circuit board may include at least oneelectrically conductive power layer (often referred to as a “voltagesupply” layer or plane), at least one electrically conductive ground orbias layer, and one or more electrically conductive signal layers thatinclude electrically conductive traces. For example, one or more signallayers may include conductive traces generally extending in a firstdirection, and one or more signal layers may include conductive tracesgenerally extending in a second direction that is substantiallyorthogonal to the first direction. Additional signal layers may also beprovided that include conductive traces generally extending at an angleto the conductive traces of the other signal layers.

Other relatively smaller circuit boards may be used in, for example,semiconductor die packages to redistribute the pattern of the bond padson a semiconductor die attached to a first side of the circuit board toa different pattern of electrical contacts on the same and/or anopposite side of the circuit board. Such circuit boards may also have alayered structure, and the conductive traces may have a custom patternconfigured for the particular semiconductor die or package in which theyare used.

To provide electrical communication between the electrical devices andcomponents through a circuit board, it may be necessary to provideelectrical communication between conductive traces in two or moredistinct layers of the circuit board. Electrically conductive vias thatextend through the thickness of at least one dielectric layer of thecircuit board are typically used to provide electrical communicationbetween the conductive traces of different layers or planes of thecircuit board. A conductive via typically includes a hole at leastpartially penetrating the circuit board. After forming the hole (bydrilling, etching, or other known technique), conductive material isprovided in the hole. A conductive trace on a first signal layer and aconductive trace on a second, distinct signal layer may each beelectrically coupled with the electrically conductive material providedin the via. The conductive traces communicating with one another throughthe conductive via may be formed or provided on the circuit board eitherprior or subsequent to forming the conductive via in the circuit board.

Conductive vias also are used to provide electrical paths through manyother types of substrates including, for example, semiconductor dice andinterposer substrates.

Differential signaling processes may be used in applications requiringextremely high-speed signal transmission and processing. Differentialsignals are signals that are referenced to each other rather than toground. As such, differential signaling requires two electricallyconductive traces for each electrical signal. The electricallyconductive traces are routed together from a driving or transmittingdevice to a receiving device, which subtracts the two signals from eachother to recover the original signal. One trace is used to carry a “truesignal phase” and a second trace is used to carry a “complementarysignal phase.” Furthermore, the conductive traces that carry the truesignal phase and the complementary signal phase are typically routedphysically close to one another and have the same or substantially thesame physical length.

FIG. 1 illustrates a portion of a circuit board 10 that includes a firstconductive trace 12 extending to a first conductive via 16, and a secondconductive trace 14 extending to a second conductive via 18. Asillustrated, the conductive vias 16, 18 may have a diameter D₀ (or othercross-sectional dimension) that is greater than a width W of each of theconductive traces 12, 14. As a result, the conductive traces 12, 14“fan-out” from one another in a region 20 proximate the conductive vias16, 18. In this configuration, the distance 22 separating the conductivevias 16, 18 differs from the distance 24 separating the conductivetraces 12, 14 in all other regions in which they extend parallel to oneanother. As a result of this increased spacing between the firstconductive trace 12 and the second conductive trace 14, a “return pathdiscontinuity” may be provided or generated by the conductive vias 16,18 when the conductive traces 12, 14 are used to carry differentialsignals, which may contribute to noise or otherwise degrade theelectrical signals carried by the conductive traces 12, 14.

A need exists for conductive vias, structures, and other features thatmaintain a constant distance between corresponding or complementaryconductive paths or traces as they extend from one plane in a substrateto another plane in the substrate.

BRIEF SUMMARY OF THE INVENTION

In one aspect, the present invention includes an electronic device thatincludes a substantially planar substrate having a hole extendingtherethrough. A first pair of electrically conductive traces extendssubstantially parallel to one another on or in the substrate, and asecond pair of electrically conductive traces extends substantiallyparallel to one another on or in the substrate. A first electricallyconductive interconnecting member extends through the hole in thesubstrate and electrically communicates with an end of a first trace ofthe first pair and an end of a first trace of the second pair. A secondelectrically conductive interconnecting member also extends through thehole and electrically communicates with an end of a second trace of thefirst pair and an end of a second trace of the second pair. The firstinterconnecting member is separated from the second interconnectingmember by a distance that is substantially equal to a distanceseparating the electrically conductive traces of the first pair and adistance separating the electrically conductive traces of the secondpair.

In another aspect, the present invention includes an electronic deviceassembly that includes a transmitting device configured to transmit adifferential signal through an electrically conductive structure to areceiving device. The electrically conductive structure includes a firstpair of electrically conductive traces that extends substantiallyparallel to one another in a first plane on or in the substrate and asecond pair of electrically conductive traces that extends substantiallyparallel to one another in a second plane on or in the substrate. Afirst electrically conductive interconnecting member extends through thehole in the substrate and electrically communicates with an end of afirst trace of the first pair and an end of a first trace of the secondpair. A second electrically conductive interconnecting member extendsthrough the hole and electrically communicates with an end of a secondtrace of the first pair and an end of a second trace of the second pair.The first interconnecting member is separated from the secondinterconnecting member by a distance that is substantially equal to adistance separating the electrically conductive traces of the first pairand a distance separating the electrically conductive traces of thesecond pair.

The transmitting device is configured to apply a differential signalbetween the conductive traces of the first pair, between the firstinterconnecting member and the second interconnecting member, andbetween the conductive traces of the second pair.

In an additional aspect, the present invention includes a method offabricating an electronic device assembly. A substantially planarsubstrate is provided that includes at least one hole extendingtherethrough. A first pair of electrically conductive traces thatextends substantially parallel to one another on or in the substrate isformed, and a second pair of electrically conductive traces that extendsubstantially parallel to one another on or in the substrate is formed.A first electrically conductive interconnecting member is formed thatextends through the hole in the substrate and electrically communicateswith an end of a first trace of the first pair and an end of a firsttrace of the second pair. A second electrically conductiveinterconnecting member is also formed that extends through the hole andelectrically communicates with an end of a second trace of the firstpair and an end of a second trace of the second pair. The firstinterconnecting member is separated from the second interconnectingmember by a distance that is substantially equal to a distanceseparating the electrically conductive traces of the first pair and adistance separating the electrically conductive traces of the secondpair.

In yet another aspect, the present invention includes a method ofdesigning an electrical device assembly comprising a transmitting deviceconfigured to transmit a differential signal to a receiving device. Asubstrate is provided that includes at least one hole extendingtherethrough, and a conductive path is selected that extends from afirst location disposed in a first plane on or in the substrate to asecond location disposed in a second plane on or in the substrate. Aportion of the conductive path extends through the hole in thesubstrate. The electrically conductive traces of a first pair of tracesare configured to extend substantially parallel to one another along aportion of the conductive path from the first location to the hole, andthe electrically conductive traces of a second pair of traces areconfigured to extend substantially parallel to one another along anotherportion of the conductive path from the second location to the hole. Afirst interconnecting member is configured to extend through the holeand communicate electrically with an end of a first trace of the firstpair and an end of a second trace of the second pair, and a secondinterconnecting member is configured to extend through the hole andcommunicate electrically with an end of a second trace of the first pairand an end of a second trace of the second pair. The firstinterconnecting member is separated from the second interconnectingmember by a distance that is substantially equal to the distanceseparating the conductive traces of the first pair from one another andthe conductive traces of the second pair from one another.

The features, advantages, and additional aspects of the presentinvention will be apparent to those skilled in the art from aconsideration of the following detailed description taken in combinationwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly pointing outand distinctly claiming that which is regarded as the present invention,the features and advantages of the various aspects of the presentinvention can be more readily ascertained from the following descriptionof the invention when read in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a plan view of a portion of a circuit board showing conductivetraces and vias;

FIG. 2 is a perspective view of an illustrative conductive structurethat embodies teachings of the present invention;

FIG. 3 is a partial top plan view of an illustrative electronic devicethat embodies teachings of the present invention;

FIGS. 4A through 4I illustrate a representative method of manufacturingthe electronic device shown in FIG. 3;

FIG. 5 is a perspective view of another illustrative conductivestructure that embodies teachings of the present invention;

FIG. 6 is a perspective view of yet another illustrative conductivestructure that embodies teachings of the present invention;

FIG. 7 is a perspective view of still another illustrative conductivestructure that embodies teachings of the present invention; and

FIG. 8 is a block diagram of an illustrative electronic system thatembodies teachings of the present invention.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

In the description which follows, like features and elements have beenidentified by the same or similar reference numerals for ease ofidentification and enhanced understanding of the disclosure hereof. Suchidentification is by way of convenience for the reader only, however,and is not limiting of the present invention or an implication thatfeatures and elements of various components and embodiments identifiedby like reference numerals are identical or constrained to identicalfunctions.

An illustrative conductive structure 30 that embodies teachings of thepresent invention is shown in FIG. 2. One or more conductive structures30 may be carried by a substrate to provide an electronic device thatembodies teachings of the present invention. By way of example and notlimitation, substrates in which one or more conductive structures 30 maybe provided include circuit boards such as, for example, relativelylarger motherboards in computer systems or relatively smaller circuitboard substrates or interposers in semiconductor device packages. Othersubstrates in which one or more conductive structures 30 may be providedinclude semiconductor dice, full or partial semiconductor wafers,silicon-on-insulator (SOI) type substrates (e.g., silicon-on-glass(SOG), silicon-on-ceramic (SOC), silicon-on-sapphire (SOS), etc.), orany substantially planar substrate that is substantially comprised of anelectrically insulating material and configured to carry electricaltraces for providing electrical communication between two or moreelectrical devices. For simplicity and to facilitate illustration, theconductive structure 30 is shown in FIG. 2 without the substrate inwhich it may be provided.

The conductive structure 30 may include a first pair 32 of electricallyconductive traces 36A, 36B and a second pair 34 of electricallyconductive traces 36C, 36D. The electrically conductive traces 36A, 36Bof the first pair 32 may extend substantially parallel to one another inor along a first plane, and the electrically conductive traces 36C, 36Dof the second pair 34 may extend substantially parallel to one anotherin or along a second plane. The second plane may be orientedsubstantially parallel to the first plane and separated therefrom by adistance. Only a portion of each of the conductive traces 36A, 36B, 36C,36D is shown in FIG. 2, and it is understood that each conductive trace36A, 36B, 36C, 36D may extend on, in, and/or through a substrate (notshown) to an electronic component or device (not shown) to which theconductive trace 36A, 36B, 36C, 36D is electrically connected.

The conductive structure 30 may further include a first interconnectingmember 40 and a second interconnecting member 42, each of which may beelectrically conductive. The first interconnecting member 40 may extendbetween and provide electrical communication between a second conductivetrace 36B of the first pair 32 and a second conductive trace 36D of thesecond pair 34. Similarly, the second interconnecting member 42 mayextend between and provide electrical communication between a firstconductive trace 36A of the first pair 32 and a first conductive trace36C of the second pair 34. Furthermore, the first interconnecting member40 may at least partially surround the second interconnecting member 42.

The second interconnecting member 42 may be separated apart from thefirst interconnecting member 40 by a distance D₁. Substantial portionsof the adjacent surfaces of the first interconnecting member 40 and thesecond interconnecting member 42 may be uniformly separated from oneanother by the distance D₁. The electrically conductive traces 36A, 36Bof the first pair 32 may be separated apart from one another over theirrespective lengths by a distance D₂. Similarly, the electricallyconductive traces 36C, 36D of the second pair 34 may be separated fromone another over their respective lengths by the same distance D₂. Byproviding a conductive structure 30 as shown in FIG. 2, the distance D₁separating the second interconnecting member 42 from the firstinterconnecting member 40 may be equal to or substantially equal to thedistance D₂ separating the conductive traces 36A, 36B of the first pair32 and the conductive traces 36C, 36D of the second pair 34. In thisconfiguration, the conductive traces 36A, 36B of the first pair 32 andthe conductive traces 36C, 36D of the second pair 34 may be configuredto carry differential signals. By interconnecting the traces 36A, 36B ofthe first pair 32 with the conductive traces 36C, 36D of the second pair34 using the first interconnecting member 40 and the secondinterconnecting member 42, return path discontinuities may be minimized,improving the quality of the electrical signals carried by theconductive traces.

In one particular embodiment of the invention, the first interconnectingmember 40 and the second interconnecting member 42 may be substantiallycoaxially arranged. For example, the first interconnecting member 40 mayhave a substantially hollow cylindrical shape, and the secondinterconnecting member 42 may have a generally solid cylindrical shape,as shown in FIG. 2. The second interconnecting member 42 may be disposedwithin the first interconnecting member 40. In this configuration, thesecond interconnecting member 42 may have an outer diameter, and thefirst interconnecting member 40 may have an inner diameter, and thedistance D₁ may be equal to one-half the difference between the outerdiameter of the second interconnecting member 42 and the inner diameterof the first interconnecting member 40.

By way of example only and not limitation, each conductive trace 36A,36B, 36C, 36D may have a thickness and width that are each less thanabout 50 microns. Furthermore, the distance D₁ and the distance D₂ mayeach be less than about 50 microns. More particularly, the distance D₁and the distance D₂ may each be less than about 30 microns. By way ofexample and not limitation, the second interconnecting member 42 mayhave an outer diameter in a range from about 20 microns to about 150microns, and the first interconnecting member 40 may have an innerdiameter in a range from about 30 microns to about 200 microns. Moreparticularly, the second interconnecting member 42 may have an outerdiameter in a range from about 100 microns to about 150 microns, and thefirst interconnecting member 40 may have an inner diameter in a rangefrom about 130 microns to about 180 microns. Furthermore, the firstinterconnecting member 40 may have an outer diameter in a range fromabout 80 microns to about 310 microns. More particularly, the firstinterconnecting member 40 may have an outer diameter in a range fromabout 260 microns to about 310 microns.

In other embodiments, the first interconnecting member 40 and the secondinterconnecting member 42 may each have a substantially hollow,generally cylindrical shape. Furthermore, the first interconnectingmember 40 and the second interconnecting member 42 may havethree-dimensional shapes such that the two-dimensional cross-sectionsthereof have shapes other than substantially circular. For example, thefirst interconnecting member 40 and the second interconnecting member 42may have three-dimensional shapes such that the two-dimensionalcross-sections thereof have shapes that are elliptical, triangular,rectangular, etc.

A top plan view of a portion of an illustrative electronic device 50that includes at least one conductive structure 30 and that embodiesteachings of the present invention is shown in FIG. 3. The electronicdevice 50 may include a substrate 52 that carries the conductivestructure 30. The substrate 52 may be or may include any of thosepreviously described in relation to FIG. 2. As shown in FIG. 3, theconductive traces 36A, 36B of the first pair 32 may be carried by anexterior surface of the substrate 52. Alternatively, the conductivetraces 36A, 36B of the first pair 32 may be carried internally withinthe substrate 52, or they may include one or more segments carried by anexterior surface of the substrate 52 and one or more segments carriedinternally within the substrate 52. Furthermore, the substrate 52 mayinclude a plurality of layers, and the conductive traces 36A, 36B of thefirst pair 32 may be carried by external or internal surfaces of thelayers of the substrate 52. Similarly, the conductive traces 36C, 36D ofthe second pair 34 may also be located externally or internally relativeto the substrate 52 as previously described in relation to theconductive traces 36A, 36B of the first pair 32.

The substrate 52 may be substantially planar, and the firstinterconnecting member 40 and the second interconnecting member 42 mayextend at least partially through the substrate 52 so as to connect endsof the conductive traces 36A, 36B with ends of the conductive traces36C, 36D. The conductive traces 36A, 36B may be disposed in a firstplane, and the conductive traces 36C, 36D may be disposed in a second,different plane. In the depicted example, interconnecting members 40, 42extend substantially through the thickness of substrate 52 and areoriented in a direction substantially normal to the major surfaces ofthe substrate 52.

A dielectric material 54 may be provided on or in the substrate 52between the conductive traces 36A, 36B of the first pair 32 and betweenthe conductive traces 36C, 36D of the second pair 34 (FIG. 2). Forexample, the dielectric material 54 may include a polymer material suchas, for example, a thermoplastic material, an epoxy, or an epoxy-basedmaterial. Commercially available dielectric solder-resist materials mayalso be used as the dielectric material 54. A dielectric material 56 maybe provided between the first interconnecting member 40 and the secondinterconnecting member 42. The dielectric material 56 may be the same asor different from the dielectric material 54.

The capacitance exhibited between the conductive traces 36A, 36B of thefirst pair 32 and between the conductive traces 36C, 36D of the secondpair 34 may be at least partially a function of the size and shape ofthe conductive traces 36C, 36D, the distance D₂ separating theconductive traces, and the dielectric constant exhibited by thedielectric material 54. Similarly, the capacitance exhibited between thefirst interconnecting member 40 and the second interconnecting member 42may be at least partially a function of the size and shape of the firstinterconnecting member 40 and the second interconnecting member 42, thedistance D₁ separating the first interconnecting member 40 and thesecond interconnecting member 42, and the dielectric constant exhibitedby the dielectric material 56.

In one embodiment, the dielectric material 56 may be selected to exhibita dielectric constant that differs from a dielectric constant exhibitedby the dielectric material 54. If the interconnecting members 40, 42 arerelatively larger than the conductive traces 36A, 36B, 36C, 36D, thecapacitance exhibited between the interconnecting members 40, 42 may belarger than the capacitance exhibited between the first pair 32 ofconductive traces 36A, 36B and the capacitance exhibited between thesecond pair 34 of conductive traces 36C, 36D. As such, the dielectricmaterial 56 and the dielectric material 54 may be selected such that thecapacitance exhibited between the first interconnecting member 40 andthe second interconnecting member 42 is similar or equal to acapacitance exhibited between the conductive traces 36A, 36B of thefirst pair 32 and a capacitance exhibited between the conductive traces36C, 36D of the second pair 34. For example, the dielectric material 56may exhibit a dielectric constant that is less than a dielectricconstant exhibited by the dielectric material 54. In this manner, returnpath discontinuities may be further minimized, thereby further improvingthe quality of the electrical signals carried by the conductive traces.

In other embodiments, the dielectric material 56 may be the same as thedielectric material 54, and the size and shape of each of theinterconnecting members 40, 42 and the conductive traces 36A, 36B, 36C,36D may be configured to minimize or eliminate differences in therespective capacitances exhibited by the interconnecting members 40, 42,the first pair 32 of conductive traces 36A, 36B, and the second pair 34of conductive traces 36C, 36D. Furthermore, combinations of thetechniques described above may be used to minimize or eliminatedifferences in capacitance. For example, the dielectric material 56 andthe dielectric material 54 may be selected to exhibit different known orpredetermined dielectric constants, and the size and shape of each ofthe interconnecting members 40, 42 and the conductive traces 36A, 36B,36C, 36D may be configured to minimize or eliminate differences in therespective capacitances exhibited by the interconnecting members 40, 42,the first pair 32 of conductive traces 36A, 36B, and the second pair 34of conductive traces 36C, 36D considering the known or predetermineddielectric constants exhibited by the dielectric material 56 and thedielectric material 54.

An illustrative method of fabricating the electronic device 50 shown inFIG. 3 is described below with reference to FIGS. 4A through 4I. FIGS.4A through 4I illustrate incremental points in an illustrative method offabricating the electronic device 50 shown in FIG. 3, taken alongsection line A-A shown therein. Referring first to FIG. 4A, a substrate52 such as, for example, a circuit board, semiconductor die, orsemiconductor wafer may be provided that includes at least theconductive traces 36A, 36B of the first pair 32 and between theconductive traces 36C, 36D of the second pair 34. In the cross-sectionalviews shown in FIGS. 4A through 4I, only the first conductive trace 36Aof the first pair 32 and the first trace 36C of the second pair 34 arevisible. The conductive traces 36A, 36B of the first pair 32 and theconductive traces 36C, 36D of the second pair 34 may extend to a generallocation 62 on the substrate 52 at which it is desired to interconnectthe conductive traces 36A, 36B of the first pair 32 and the conductivetraces 36C, 36D of the second pair 34 through the substrate 52.

By way of example and not limitation, the conductive traces 36A, 36B ofthe first pair 32 and the conductive traces 36C, 36D of the second pair34 may be formed on or in the substrate 52 by, for example, depositing athin layer of conductive material (such as, for example, metals andmetal alloys including one or more of gold, copper, aluminum, silver)and patterning the conductive traces 36A, 36B, 36C, 36D in the thinlayer of conductive material by, for example, masking and etching (wetor dry) the thin layer of conductive material. Such a thin layer ofconductive material may be deposited by, for example, physical vapordeposition (PVD) techniques (e.g., sputtering), chemical vapordeposition (CVD) techniques, electroplating techniques, electrolessplating techniques, etc. Alternatively, a conductive film may belaminated to both sides of the substrate 52. The conductive film mayinclude preformed conductive traces 36A, 36B, 36C, 36D, or theconductive traces 36A, 36B, 36C, 36D may be subsequently formed orpatterned in the conductive film.

In the example shown in FIG. 4A, the conductive traces 36A, 36B of thefirst pair 32 may be carried by a first major surface 58 of thesubstrate 52 and the conductive traces 36C, 36D of the second pair 34may be carried by an opposite, second major surface 60 of the substrate52.

A dielectric material 54 optionally may be provided on the first majorsurface 58 and the second major surface 60 of the substrate 52,including the areas between the conductive traces 36A, 36B, 36C, 36D.

As shown in FIG. 4B, a hole or aperture 66 may be punched, drilled,etched, or otherwise formed through the substrate 52 from the firstmajor surface 58 to the second major surface 60. For example, a lasermay be used to ablate the material of the substrate 52 to form theaperture 66 through the substrate 52. Mechanical punching and drillingprocesses or chemical etching processes may also be used, as maycombinations of processes, to form and shape the aperture 66 through thesubstrate 52. The aperture 66 may communicate with ends of eachconductive trace 36A, 36B of a first pair 32 and with ends of eachconductive trace 36C, 36D of a second pair 34 (FIG. 2). In someembodiments, the aperture 66 may be formed subsequent to formation ofthe conductive traces 36A, 36B, 36C, 36D. In other embodiments, however,the aperture 66 may be formed prior to formation of the conductivetraces 36A, 36B, 36C, 36D.

Referring to FIG. 4C, a first interconnecting member 40 may be formed bydepositing a layer of conductive material 68 at least over the exposedlateral surfaces 70 of the substrate 52 within the aperture 66. By wayof example and not limitation, the layer of conductive material 68 maybe deposited over all exposed surfaces of the structure, including theexposed lateral surfaces 70 of the substrate 52 within the aperture 66,using, for example, electroplating techniques, electroless platingtechniques, or physical vapor deposition techniques to form thestructure shown in FIG. 4C.

The layer of conductive material 68 (FIG. 4C) may be selectivelypatterned to remove the unwanted areas of the layer of conductivematerial 68 deposited on surfaces outside the aperture 66 and form thestructure shown in FIG. 4D. In some embodiments, unwanted areas of thelayer of conductive material 68 deposited on surfaces inside theaperture 66 may also be selectively patterned and removed. The layer ofconductive material 68 may be selectively patterned by, for example,masking and etching (wet or dry) the layer of conductive material 68. Asseen in FIG. 4D, if the conductive traces 36A, 36B, 36C, 36D have beenpreviously formed, the first interconnecting member 40 may bestructurally and electrically coupled to both of the conductive traces36A, 36B of the first pair 32 and to both of the conductive traces 36C,36D of the second pair 34 upon formation of the first interconnectingmember 40.

Referring to FIG. 4E, a first aperture, groove, void, or notch 74 may beformed in the first interconnecting member 40 so that the firstconductive trace 36A of the first pair 32 may be electrically isolatedfrom the first interconnecting member 40, and a second aperture, groove,void, or notch 76 may be fowled in the first interconnecting member 40so that the first conductive trace 36C of the second pair 34 may beelectrically isolated from the first interconnecting member 40. By wayof example and not limitation, the first notch 74 and the second notch76 may be formed by etching (wet or dry) the first interconnectingmember 40 through a mask. Other methods such as, for example, electronbeam lithography may also be used to form the first notch 74 and thesecond notch 76 in the first interconnecting member 40. If theconductive traces 36A, 36B, 36C, 36D have been previously formed, thesecond conductive trace 36B of the first pair 32 and the secondconductive trace 36D of the second pair 34 (FIG. 2) may remainstructurally and electrically coupled to the first interconnectingmember 40. As previously discussed, however, in some embodiments theconductive traces 36A, 36B, 36C, 36D may be formed subsequent toformation of the first interconnecting member 40 and the secondinterconnecting member 42.

In some embodiments, the first notch 74 and the second notch 76 may beformed at the same time the layer of conductive material 68 isselectively patterned to remove the unwanted areas of the layer ofconductive material 68 deposited on surfaces outside the aperture 66, aspreviously discussed.

The aperture 66, the first notch 74, and the second notch 76 may befilled with dielectric material 56 to form the structure shown in FIG.4F. By way of example and not limitation, a curable fluid polymermaterial such as, for example, an epoxy or epoxy-based material may beprovided within the aperture 66, the first notch 74, and the secondnotch 76 and subsequently consolidated or cured to form a substantiallyrigid structure comprising the dielectric material 56. As an alternativemethod, a curable polymer material may be provided within the aperture66, the first notch 74, and the second notch 76 and subsequentlyconsolidated or cured using programmed material consolidation techniquessuch as, for example, photolithography techniques. In such techniques,multiple layers or regions of consolidated material may be sequentiallyformed within the aperture 66, the first notch 74, and the second notch76 using an at least partially automated machine.

In some embodiments of the present invention, a curable fluid polymermaterial such as, for example, an epoxy or epoxy-based material may beblanket deposited over the substrate 52 including within the aperture66, the first notch 74, and the second notch 76 and subsequentlyselectively consolidated or cured only at selected regions such as inthe aperture 66, the notches 74, 76, and/or between the first pair 32 ofconductive traces 36A, 36B and between the second pair 34 of conductivetraces 36C, 36D. The regions of curable fluid polymer material that havenot been consolidated or cured then may be washed or rinsed away. If thesubstantially rigid structure comprising the dielectric material 56 isnot selectively provided within aperture 66, the notches 74, 76, and/orbetween the first pair 32 of conductive traces 36A, 36B and between thesecond pair 34 of conductive traces 36C, 36D, the structure optionallymay be planarized to remove unwanted regions of dielectric materialdisposed outside the aperture 66 using, for example, known etching orchemical-mechanical polishing (CMP) techniques.

In some embodiments of the present invention, the dielectric material 54may be identical to the dielectric material 56, and may besimultaneously deposited onto the substrate 52 after forming theaperture 66.

Referring to FIG. 4G, a first aperture, groove, void, or notch 78 may beformed in the dielectric material 56 that extends from an end of theconductive trace 36A to a location in the dielectric material 56 atwhich the second interconnecting member 42 (FIG. 2) is to be formed, anda second aperture, groove, void, or notch 80 may be formed in thedielectric material 56 that extends from an end of the conductive trace36C to a location in the dielectric material 56 at which the secondinterconnecting member 42 (FIG. 2) is to be formed. By way of exampleand not limitation, the first notch 78 and the second notch 80 may beformed by etching (wet or dry) the dielectric material 56 through amask. Other methods such as, for example, electron beam lithography mayalso be used to form the first notch 78 and the second notch 80 in thedielectric material 56. Furthermore, if the dielectric material 56 isprovided in or on the substrate 52 in a liquid form and subsequentlyconsolidated or cured using a selective consolidation technique aspreviously described, the first notch 78 and the second notch 80 may beformed in the dielectric material 56 when the dielectric material 56 isselectively consolidated by failing to consolidate dielectric material56 in the regions at which the first notch 78 and the second notch 80are to be formed.

As shown in FIG. 4H, an additional hole or aperture 82 may be punched,drilled, etched, or otherwise formed through the dielectric material 56,as previously described in relation to the aperture 66 shown in FIG. 4B.Similar to the notches 78, 80 in the dielectric material 56, if thedielectric material 56 is provided in or on the substrate 52 in a liquidform and subsequently consolidated or cured using a selectiveconsolidation technique as previously described, the additional hole oraperture 82 shown in FIG. 4H may be formed in the dielectric material 56when the dielectric material 56 is selectively consolidated by failingto consolidate dielectric material 56 in the region at which theadditional hole or aperture 82 is to be formed.

The aperture 82, the first notch 78, and the second notch 80 in thedielectric material 56 then may be filled with an electricallyconductive material to form the second interconnecting member 42 (FIG.2), and the final electronic device 50, as shown in FIG. 4I. By way ofexample and not limitation, the aperture 82, the first notch 78, and thesecond notch 80 in the dielectric material 56 may be filled with anelectrically conductive material using, for example, electroplatingtechniques, electroless plating techniques, or physical vapor depositiontechniques. Any excess conductive material deposited on the structuremay be removed by, for example, masking and etching the structure aspreviously described herein.

It is understood that other methods, sequences, or processing methodsmay be used to form the final electronic device 50 shown in FIGS. 3 and4I. For example, in one additional method according to the invention,the aperture 82 shown in FIG. 4H may be formed through the dielectricmaterial 56 prior to forming the first notch 78 and the second notch 80in the dielectric material, as previously described in relation to FIG.4G. In yet another additional method, instead of filling the entireaperture 66 shown in FIG. 4E with dielectric material 56 as describedabove in relation to FIG. 4F and subsequently forming another aperture82 through the dielectric material 56 as described above in relation toFIG. 4H, a relatively thin layer of dielectric material 56 may bedeposited on the lateral surfaces of the first interconnecting member 40within the aperture 66 (FIG. 4E) using an electrocoating process, suchas that described in U.S. Pat. No. 6,829,133 to Wermer et al., thedisclosure of which is hereby incorporated herein in its entirety bythis reference. In this method, there may be no need to form anadditional aperture 82 through the dielectric material 56.

In the conductive structure 30 shown in FIG. 2, and the electronicdevice 50 shown in FIGS. 3 and 4I, which includes the conductivestructure 30, the conductive traces 36A, 36B of the first pair 32 andthe conductive traces 36C, 36D of the second pair 34 are shown extendingaway from the first interconnecting member 40 and the secondinterconnecting member 42 in substantially the same direction onopposite sides of the substrate 52.

Another illustrative conductive structure 84 that embodies teachings ofthe present invention is shown in FIG. 5. The conductive structure 84 issimilar to the conductive structure 30 and includes a first pair 32 ofelectrically conductive traces 36A, 36B, a second pair 34 ofelectrically conductive traces 36C, 36D, a first interconnecting member40, and a second interconnecting member 42. In the conductive structure84, however, the electrically conductive traces 36A, 36B of the firstpair 32 extend away from the first interconnecting member 40 and thesecond interconnecting member 42 in a direction that is oriented at anangle relative to a direction in which the electrically conductivetraces 36C, 36D of the second pair 34 extend away from the firstinterconnecting member 40 and the second interconnecting member 42. Theangle between the directions in which the conductive traces 36A, 36B ofthe first pair 32 and the conductive traces 36C, 36D of the second pair34 extend away from the first interconnecting member 40 and the secondinterconnecting member 42 may be any angle between 0 degrees and 360degrees.

Conductive structures that embody teachings of the present invention mayinclude more than two conductive traces and correspondinginterconnecting members. Yet another conductive structure 86 thatembodies teachings of the present invention is shown in FIG. 6. Theconductive structure 86 is similar to the conductive structure 84 shownin FIG. 5. As illustrated in FIG. 6, however, the conductive structure86 may include a first set 88 of electrically conductive traces 36E,36F, 36G, a second set 90 of electrically conductive traces 36H, 36I,36J, a first interconnecting member 40, a second interconnecting member42, and a third interconnecting member 44. The first interconnectingmember 40 may be structurally and electrically coupled to an end of theconductive trace 36G and an end of the conductive trace 36H, the secondinterconnecting member 42 may be structurally and electrically coupledto an end of the conductive trace 36F and an end of the conductive trace36I, and the third interconnecting member 44 may be structurally andelectrically coupled to an end of the conductive trace 36E and an end ofthe conductive trace 36J. In other embodiments, the conductive structure86 may include any number of conductive traces and correspondinginterconnecting members as desired.

Another illustrative conductive structure 91 that embodies teachings ofthe present invention is shown in FIG. 7. The conductive structure 91 issubstantially similar to the conductive structure 30 shown in FIG. 2. Inthe conductive structure 91, however, the first conductive trace 36A ofthe first pair 32 is disposed vertically above the second conductivetrace 36B of the first pair 32, as opposed to the horizontallyside-by-side configuration shown in FIG. 2. In a similar manner, thefirst conductive trace 36C of the second pair 34 is disposed verticallybelow the second conductive trace 36D of the second pair 34. Adielectric material (not shown) may be disposed between the conductivetraces 36A, 36B of the first pair 32 and the conductive traces 36C, 36Dof the second pair 34 when the conductive structure 91 is disposed in asubstrate (not shown) as previously described.

A block diagram of an illustrative electronic system 92 that embodiesteachings of the present invention is shown in FIG. 8. The electronicsystem 92 includes a substrate 52 (such as, for example, a circuitboard) comprising an electrically conductive structure that embodiesteachings of the present invention such as, for example, the conductivestructure 30 shown in FIG. 2. The system 92 further includes at leastone electrical component 94 attached to the substrate 52, and at leastone additional electrical component 96. In one particular embodiment,the electrical component 94 and the electrical component 96 may eachinclude an integrated circuit device, as shown in FIG. 8. For example,the electrical component 94 may include a memory device, and theelectrical component 96 may include an electronic signal processordevice (often referred to as a “microprocessor”).

In other embodiments, the electrical component 94 may include anintegrated circuit device such as a memory device or an electronicsignal processor device, and the electrical component 96 may include,for example, an electronic signal controller device. Moreover, both theelectrical component 94 and the electrical component 96 may be attachedto the substrate 52.

The electronic system 96 may, optionally, further include one or moreinput/output devices 98 such as, for example, a mouse or other pointingdevice, keyboard, control panel, monitor, printer, etc., which maycommunicate electrically with at least one of the electrical component94 and the electrical component 96.

With reference to FIGS. 2 and 8 together, the electrical component 94may be electrically coupled to the conductive traces 36A, 36B of thefirst pair 32, and the electrical component 96 may be electricallycoupled to the conductive traces 36C, 36D of the second pair 34. In thisconfiguration, electrical communication may be enabled and establishedbetween the electrical component 94 and the electrical component 96through the conductive trace 36A, the second interconnecting member 42,and the conductive trace 36C, and through conductive trace 36B, thefirst interconnecting member 40, and the conductive trace 36D. In thisconfiguration, the electrical component 94 and the electrical component96 may be configured to electrically communicate with one anotherthrough the conductive structure 30 using differential signalingtechniques. At least one of the electrical component 94 and theelectrical component 96 may be configured to provide a differentialsignal between the conductive traces 36A, 36B of the first pair 32,between the first interconnecting member 40 and the secondinterconnecting member 42, and between the conductive traces 36C, 36D ofthe second pair 34. In certain embodiments, at least one of theelectrical component 94 and the electrical component 96 may beconfigured to provide a voltage difference of less than about threevolts between the conductive traces 36A, 36B of the first pair 32,between the first interconnecting member 40 and the secondinterconnecting member 42, and between the conductive traces 36C, 36D ofthe second pair 34. D

In other embodiments, at least one of the electrical component 94 andthe electrical component 96 may be configured to provide an electricalsignal through the conductive trace 36A of the first pair 32, the secondinterconnecting member 42, and the conductive trace 36C of the secondpair 34, and the conductive trace 36B of the first pair 32, the firstinterconnecting member 40, and the conductive trace 36D of the secondpair 34 then may be used as a controlled impedance line to shield theconductive trace 36A, the second interconnecting member 42, and theconductive trace 36C from electromagnetic interference. Similarly, atleast one of the electrical component 94 and the electrical component 96may be configured to provide an electrical signal through the conductivetrace 36B of the first pair 32, the first interconnecting member 40, andthe conductive trace 36D of the second pair 34, and the conductive trace36A of the first pair 32, the second interconnecting member 42, and theconductive trace 36C of the second pair 34 then may be used as acontrolled impedance line to shield the conductive trace 36B, the firstinterconnecting member 40, and the conductive trace 36D fromelectromagnetic interference.

The teachings of the present invention may provide conductive vias,structures, and other features that maintain a constant distance betweencorresponding or complementary conductive paths or traces as they extendfrom one plane in a substrate to another plane in the substrate.Furthermore, the teachings of the present invention may be used tominimize the amount of area or “real estate” on a substrate required forconductive vias that extend from one plane in a substrate to anotherplane in the substrate.

While the present invention has been described in terms of certainillustrated embodiments and variations thereof, it will be understoodand appreciated by those of ordinary skill in the art that the inventionis not so limited. Rather, additions, deletions and modifications to theillustrated embodiments may be effected without departing from thespirit and scope of the invention as defined by the claims which follow.

What is claimed is:
 1. An electronic device assembly comprising: anelectrically conductive structure on or in a substrate, the electricallyconductive structure comprising: a first pair of electrically conductivetraces extending substantially parallel to one another in a first plane;a second pair of electrically conductive traces extending substantiallyparallel to one another in a second plane; an electrically conductivefirst interconnecting member extending between and electricallycommunicating with an end of a first trace of the first pair and an endof a first trace of the second pair; and an electrically conductivesecond interconnecting member extending between and electricallycommunicating with an end of a second trace of the first pair and an endof a second trace of the second pair, the first interconnecting memberat least partially surrounding the second interconnecting member,wherein at least a portion of the second interconnecting member ispositioned between portions of the first interconnecting member; atransmitting device configured to transmit a differential signal throughthe electrically conductive structure, the differential signal appliedbetween the electrically conductive traces of the first pair, betweenthe first interconnecting member and the second interconnecting member,and between the electrically conductive traces of the second pair; and areceiving device configured to receive the differential signaltransmitted by the transmitting device.
 2. The electronic deviceassembly of claim 1, wherein the second plane is oriented substantiallyparallel to the first plane and separated therefrom by a distance. 3.The electronic device assembly of claim 1, wherein a distance separatingthe first interconnecting member from the second interconnecting memberis substantially equal to a distance separating the first pair ofelectrically conductive traces and a distance separating the second pairof electrically conductive traces.
 4. The electronic device assembly ofclaim 3, wherein the first interconnecting member has a hollowsubstantially cylindrical shape having an inner diameter, and whereinthe second interconnecting member has a substantially cylindrical shapehaving an outer diameter, the second interconnecting member beingdisposed within the first interconnecting member, the distance betweenthe outer diameter of the second interconnecting member and the innerdiameter of the first interconnecting member being substantially equalto the distance separating the electrically conductive traces of thefirst pair and the distance separating the electrically conductivetraces of the second pair.
 5. The electronic device assembly of claim 4,wherein the second interconnecting member has a generally solidcylindrical shape.
 6. The electronic device assembly of claim 4, whereinthe first interconnecting member and the second interconnecting memberare substantially coaxially arranged.
 7. The electronic device assemblyof claim 3, wherein the distance separating the first interconnectingmember from the second interconnecting member is less than about 30microns.
 8. The electronic device assembly of claim 1, wherein the firstpair of electrically conductive traces extends in a first direction inthe first plane, and wherein the second pair of electrically conductivetraces extends in a second direction in the second plane, the seconddirection being oriented at an angle relative to the first direction. 9.The electronic device assembly of claim 1, further comprising adielectric material disposed between the first interconnecting memberand the second interconnecting member.
 10. The electronic deviceassembly of claim 9, wherein the dielectric material comprises a polymermaterial.
 11. The electronic device assembly of claim 10, wherein thedielectric material comprises an epoxy or epoxy-based material.
 12. Theelectronic device assembly of claim 9, wherein the dielectric materialexhibits a dielectric constant that provides a capacitance between thefirst interconnecting member and the second interconnecting membersubstantially equal to a capacitance between the electrically conductivetraces of the first pair and a capacitance between the electricallyconductive traces of the second pair.
 13. The electronic device assemblyof claim 1, wherein the transmitting device and the receiving deviceeach comprise one of a microprocessor device and a memory device. 14.The electronic device assembly of claim 1, wherein the transmittingdevice is configured to apply a voltage difference of less than aboutthree volts between the electrically conductive traces of the firstpair, between the electrically conductive traces of the second pair, andbetween the first interconnecting member and the second interconnectingmember.
 15. The electronic device assembly of claim 1, wherein the firstinterconnecting member has a hollow at least substantially cylindricalshape comprising a first aperture, wherein the second conductive traceof the first pair of conductive traces extends through the firstaperture and is electrically isolated from the first interconnectingmember.
 16. The electronic device assembly of claim 1, wherein the firstinterconnecting member has a hollow at least substantially cylindricalshape comprising a second aperture wherein the second conductive traceof the second pair of conductive traces extends through the secondaperture and is electrically isolated from the first interconnectingmember.
 17. The electronic device assembly of claim 1, wherein at leastone of the first interconnecting member and the second interconnectingmember comprises a cross-sectional shape that is one of triangular,elliptical, rectangular, and cylindrical.